The main goal of this pilot project is to assess the feasibility (a) of identifying patients with abnormal spatiotemporal hyperacuity and (b) of dissecting in this way the interpolation mechanism. Spatiotemporal interpolation is responsible not only for vernier acuity measured in the laboratory, and for the effectiveness of cinematography, but also for the sharp, unsmeared and precise perception of moving objects experienced in everyday life. While dissecting the mechanism underlying spatiotemporal interpolation in terms of data from abnormal subjects, we will study some aspects of the pathology and development of hyperacuity. While standard visual acuity (two joint or grating acuity) mainly depends on retinal factors, hyperacuity is very likely to reflect cortical properties. Thus, tests of spatial and temporal hyperacuity may turn out to provide useful diagnostic or prognostic information.